When playing against Germans with the Tiger Ace, I spend almost all my manpower on Zis guns and try to get 2-4 if possible.
I usually have either SU-85 or IS-2. On rarer occasion, I may have an ISU-152.
I bind the tanks to 1 and the zis guns to 2.
Then I try to track down the Tiger Ace and throw this group of Zis guns at him first. I never use tanks against it first; always Zis. Ideally I have 3 or 4 zis guns pummelling it while my IS-2 (with its good frontal armor and hp), shoots its rear and scoots backward to reload.
Then I try to trap it from the rear with the tanks with long range shoot & scoot shooting.
All that is assuming you have nothing else to do with your army and that the enemy has no units in suppot.
I think I've seen this be the case maybe once.
It does require much luck to work. I.e. it's not a Cook book kind of conter-strategy.